I took it off today, it's about 1.75" at the charge pipe and 1.5" at the turbo. The coupler hose is 3.19" in length. Most of the silicone couplers I've found on the web are 3" length, so that's a tad too short.
The stock factory black bands are actually just plastic. They have a V-form so they grip the 2nd raised portion of the charge pipe. I think this was just loose and allowed a lot of the gunk to come out under boost. Once I used a new liner clamp, the vacuum leak sound I was hearing at the firewall is now gone, but another hissing sound is somewhere in the engine compartment.
I used a dremel wheel and didn't realize the bands aren't completely smooth underneath (where it touches the hose). It's more of a concave design to fit the pipe better, so it's actually thinner than it looks. A fast cut is all that's needed. I went a tad too deep and hit maybe 1mm of the hose. Just use a screwdriver to slip directly into the slit and crack it apart.
I also bought a new throttle body cap for the motor and used a hose clamp and vacuum cap to cover that section. Like I assumed, that was a vacuum leak as well. For those that no longer have a cap, that means the throttle body shaft seal (or another seal) is no longer functional, allowing air to go into the intake manifold through the shaft - or allows air to exit under boost. This is probably how the caps pop out. I can see this vacuum cap collapse at idle.
I can see why Ford went with speed density for their EcoBoost engines. With all the vacuum/boost leaks going on, a traditional MAF system would go nuts.